Magnetic resonance imaging assessment of thickened ligamentum flavum in degenerative lumbar spine-corelation with age, gender, degenerative disc, right-left asymmetry in central india population

Background: Thickened ligamentum flavum(LF) has been traditionally related to lumbar canal stenosis. Till date many studies has been done to evaluate thickened LF and its association with age, gender, disc degeneration, mean LF thickness, increment in LF thickness at lumbar levels and right-left asymmetry or side dominance. But many discrepancies were found. Present study aimed to study these associations in the central India population.
Material and methods: 345 individuals of 20 to 70 years old, with complains of low back ache and/ or leg pain whose Magnetic Resonance Imaging (MRI)of lumbosacral spine was done , were studied retrospectively. LF thickness was measured on axial T1WI of MRI at L3-4,L4-5 and L5-S1 levels. Mean and standard deviations of the parameters and t tests were taken. Significant difference was set at P < 0.05.
Results: LF thickness significantly increased with age at all levels and was more thicker in females than males. Increment was larger at L4-5 than at L5-S1 level. Increased LF thickness was observed with type IV –V disc degeneration, but was not statistically significant (p>0.05). Mean LF thickness at L5-S1 level on right side was found to be more i.e 4.56 mm followed by L4-5(right-4.36 ,left-3.70mm) and L3-4 level(right-3.63mm ,left-2.86mm). Mean thickness at L5-S1level on left side was found to be less i.e 1.28mm. Significant asymmetry was found between LF thickness on right and left side at each lumbar level and right sided dominance was found at each level.
Conclusion: LF thickness is an age and gender dependent phenomenon. Right sided dominance is found at each lumbar level. LF thickness is increased at L5-S1 level and L4-5 levels.